I was being sarcastic because there isn't any logical reason your video playback is sucking. We were given TWO FACTORS (decent card and processor speed), and that's insufficient for anybody to throw out the answer (unless you felt like listing every single possible explanation).
So PLEASE, Don't pull the forum enforcer act out of your skirt. "Normal community members" should at least expect posts to be written with sufficient information and correct spelling. This isn't a freakin' haXX0r' forum. Get with the program.